Tuesday, February 24, 2009

Solar Cell

Physics Behind Solar Cell

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Wednesday, February 18, 2009

Photovoltaic Energy Conversion

Photovoltaic energy refers to the direct conversion of the energy in light into usable electrical energy which then can be employed or stored. These could be seen as light-induced transition from ground state to excited state, a transport mechanism which conveys away the resulting excited electrons and holes, and a “check valve” of some sort which prevents these photo-generated electrons and holes from flowing backwards and recombining. In such a system the electrons, whose energy has been pumped up by the incoming photons, must go through some external path in order to lose their energy and recombine with the holes. This external path may involve an electrical load or some storage mechanism such as chemical storage (batteries).

It is very similar to natural photosynthesis as seen in the schematic above. Again these is a light-induced transition from ground state to excited state (in this case, two are seen) and a transport mechanism with a check valve. In the energy conversion system devised by nature the excited electrons and holes are used directly to store energy in chemical bonding.

Tuesday, February 17, 2009

More than 1,300 Solar Megawatts!!!

While many countries invest in renewable energy related matters, the other day I found some information about the biggest installation in history, that will be constructed by the utility Southern California Edison and solar power plant maker, BrightSource.

This solar installation will produce the same amount of electricity than 1 modern nuclear reactor.

To see an equivalent, nuclear plants normally have 1 reactor, some of them could even reach 2, 3, or even more. The biggest nuclear plant in the United States is Palo Verde Nuclear Generating Station, Arizona, which has 3 reactors. Reactors 1,2 are producing the same amount of electricity than this new solar park, 1,300 Megawatt!!!

When this installation will be fully operational (probably by 2013), it will provide enough electricity to 845,000 home – more than exist in San Francisco.

The technology used in this station will be thermal power, which basically concentrates the sun’s energy (rays) to create steam, which will spin a turbine and then electricity will be generated.

See Article in wired

Solar Decathlon

In the last 10 years many different contests are appearing throughout the world to educate and raise awareness of solar energy production.

Lately I attended to an interesting talk, done by students from "University of Missouri-Rolla and Rolla Institute". They are involved in a Competition done by the U.S. Department of Energy: “Solar Decathlon”. In this competition 20 teams from different colleges and universities around the world compete to design, and operate the most attractive, effective, and energy-efficient solar-powered house.

Most of the information provided was really interesting, but what attract me the most was the encouraging view of the students, who have actually been in this project for 2 years and they are building the own solar village.

You coul more information in: (http://www.solardecathlon.org/).

Monday, February 16, 2009

Conservation vs. Generation

There are two main points regarding Renewable Energy: Conservation and Generation.

Generation is basically the process of converting non-electrical energy to electricity.
Conservation will be basically trying to enhance the already electrical systems, such as air conditioning, heater, and so forth to adapt to them to a lower usage of electricity.

Someone could say that energy can't be created or destroyed as the law of conservation of energy states, that energy in an isolated system remains constant. Therefore energy cannot be created or destroyed. But with Solar, Wind and other technologies we are simply trying to reduce the quantity of watts in use, so aren't wrongly interpreting this law, simply adapting for our purpose: "become as low fossil fuel independent as possible" or "make as much money as possible", depending completely on the point of view.

Renewable Energy?


Lately renewable energy have become more and more important. The main problem with renewable energy is what also happens with organic food: too many definitions, and too many interpretations. What exactly we mean with renewable? While reading articles, books, and searching through the web I have found hundreds of different definitions, but there was only two that everyone will probably accept.

"Energy resources such as wind power or solar energy that can keep producing indefinitely without being depleted".

"Renewable Energy is energy generated from natural resources which are naturally replenished".

  • Biomass
  • Geothermal
  • Hydro Power
  • Tidal Power
  • Wind Power
  • Solar Power